Bag with tear strip

ABSTRACT

Plastic film having extending wholly or partly across it a flexible reinforcement having a highly localised line of weakness, the reinforcement being bonded to the surface of the film or incorporated partly or wholly within its thickness. The reinforcement may be, for example, a woven textile web material or plastic sheet. The resulting film may be used to make containers which can be easily opened by tearing along the line or lines of weakness in the reinforcement.

United States Patent [1 1 Cross et al.

[ Sept. 18, 1973 BAG WITH TEAR STRIP [75] Inventors: William TelfordCross, Cuddington;

Margaret Lilian Steel, Runcorn; Stephen Edward Trueman, Warrington, allof England [73] Assignee: Imperial Chemical Industries Limited, London,England 22 Filed: Apr. 9, 1971 211 App]. No.: 132,674

[30] Foreign Application Priority Data Apr. 14, 1970 Great Britain17,687/70 [52] U.S. Cl. 229/66, 229/62 [.51] Int. Cl B65d 33/00 [58]Field'of Search 229/66, 51 AS, 85

[56] References Cited UNITED STATES PATENTS 3,616,990 11/1971 Powell229/66 3,088,654 5/1963 Peril 10 229/85 3,146,912 9/1964 Twersky....229/66 3,341,108 9/1967 Kirlc 229/66 3,446,632 5/1969 Le Van 229/85 XFOREIGN PATENTS OR APPLICATIONS 1,359,938 3/1964 France 229/66 PrimaryExaminer-Donald F. Norton Attorney-Cushman, Darby & Cushman [57]ABSTRACT Plastic film having extending wholly or partly across it aflexible reinforcement having a highly localised line of weakness, thereinforcement being bonded to the surface of the film or incorporatedpartly or wholly within its thickness. The reinforcement may be, forexample, a woven textile web material or plasticsheet. The resultingfilm may be used to make containers which can be easily opened bytearing along the line or lines of weakness in the reinforcement.

5 Claims, 29 Drawing Figures PATENTED SE?! 8 I975 SHEET 1 OF 5 PATENTEUSEFI 8l975 SHEET 2 OF 5 PATENTEDSEPI a 1975 5 9 sum 5 BF 5 BAG WITH TEARSTRIP This invention relates to articles of plastic film, and inparticular to articles of improved tearability comprising plastic filmwhich is normally tearable only with difficulty.

Many articles of plastic film, for example films of polyethylene andpoly(ethylene terephthalate), are tearable only with difficulty; or ifvery weak, they tend to tear in a haphazard fashion, normally becausestretching of the film occurs before or during the tearing operation.

According to the present invention there is provided plastic film whichhas extending partly or wholly across it flexible reinforcement having ahighlylocalised line of weakness, said reinforcement being bonded to thesurface of the film or incorporated partly or wholly within itsthickness.

The invention is particularly applicable to bags, sacks and othercontainers made from or comprising such plastic film, e. g. containersof the heat-sealed kind used for packaging frozen foods, confectionery,fertilisers and other goods which need to be protected from air and/ormoisture. Where it is required that the tear commence at an edge of thefilm, as where a single sheet of film is to be torn, or at a commonedge, as where a sheet of film is folded or where two sheets of filmmeet, the reinforcement and the line of weakness conveniently extendsfrom that edge. Thus, in a further embodiment, we provide a bag or sackhaving two walls of the reinforced plastic film of the invention,wherein each reinforcement extends from a common edge for the two walls,preferably to another common edge of the said walls, and thereinforcements are arranged such that the lines of weakness aresuperimposible or substantially so. Preferably the reinforcement alsoextends outwardly beyond the edge of the wall or walls and has anincision in this extension leading into the line of weakness. When asingle sheet of film is to be torn the reinforcement may be applied toone side of the film or to both sides. Where two sheets are to be tornsimultaneously, as in tearing ,open a bag, then conveniently each sheetwill have reinforcement on one side only. 4

As examples of plastic film which has been reinforced according to theinvention may be mentioned polyethylene, polypropylene, poly(ethyleneterephthalate), polyamide and polyvinyl chloride, and laminates e.g.plastic/paper, and plastic/metal foil laminates, e.g.polyethylene/aluminum laminates as well as plastic/- plastic laminates.i

The reinforcement may be a woven textile web which is long in comparisonto its width, e.g. a tape or strip of scrim, e.g. of cotton or linen, orof net, e.g. nylon net of the kind commonly used for curtaining.Alternatively, it may comprise a pair of strips of film or tape whichare arranged parallel and in abutting or closely spaced relationship.The reinforcement is disposed in such a way that a line of weaknessextends in the required tear direction. Where the reinforcement consistsof a single woven textile web, the required line of weakness is definedby any two adjacent warp or weft threads. Selection of the reinforcingmaterial will, of course, be made with its ease of tearability in mind.Very strong reinforcing material, such as it itself difficult to tear,will not be employed.

' welding techniques employing solvents for the film it- Where thereinforcement is a pair of parallel abutting or closely spaced strips,the line of weakness lies between the two strips.

An alternative reinforcing material is a plastic, or a thin metal sheetor strip; this may be of any material which can be bonded to orincorporated partly or wholly within the thickness of the film and whichis compatible with the film and the use to which the film is put.Examples of such reinforcing materials which conveniently may beemployed as a pair of strips arranged parallel and in abutting orclosely spaced relationship are adhesive regenerated cellulose strip,e.g. Sellotape (RTM), polyamide plastics e.g. nylon, polyesters,e.g.poly(ethylene terephthalate), polyvinylchloride, polyethylene andpolypropylene; other plastic materials which may be used according tothe invention will be apparent to the man skilled in the art. Totalwidth of the reinforcing strip will usually be 0.2-1 inch, preferably0.3-0.75 inch and its length (i.e. in contact with thefilm) preferablyat least one inch.

While it may be convenient to apply to the plastic film reinforcement inthe form of a preformed strip or tape, where the reinforcing material issoluble or dispersible in a liquid medium we have found that it may i beapplied to the film in liquid or paste form, e.g. in solution or insuspension e.g. in a highly volatile medium which can-be evaporatedquickly. Thus, the reinforcement, in liquid or paste form, may beapplied to the film so as to provide the required localised line ofweakness, e.g. by painting or printing on to the film two parallel linesof reinforcement. Obviously the reinforcement must be capable of bondingto the film after evaporation of any solvent or suspending medium, orafter curing if a curable reinforcement is applied in an uncured state;the selection of compatible film and reinforcement will present nodifficulty to the skilled man. As

examples of such reinforcement compositions may be mentioned ink andpaint compositions containing polymeric materials in solution orsuspension e.g. polyurethane, polyvinylchloride and acrylic basedpaints. The requirement is that when dried or cured, as the case may be,the reinforcement can form a continuous sheet which has sufficienttensile strength to retain its integrity and which bonds to the filmsufficiently strongly, when employed according to the invention, toprovide the desired reinforcing effect. Such reinforcement is suitablyapplied to give a thickness for the dry reinforcement within the range0.1-2 mm preferably 0.2-.1 mm.

The reinforcement may be applied to the surface-of the plastic film or,if it is in strip or tape form, incorporated partly or wholly within itsthickness. For example,

it may be bondedto the surface, rolled on to heatsoftened film (e.g.immediately after extrusion), or rolled into heat-softened film (e.g.immediately after extrusion) or the combination may be submitted toradio frequency welding. Where the reinforcement is,

bonded to the surface using an adhesive, adequate adhesion may beobtained by use of a pressure sensitive adhesive, although otheradhesives, e.g. heat cure-or solvent types may be employed, as also maysolvent self; all that is required of the bond between the reinforcementand the film is that the line of weakness is defined, and that thestrength of the: bond is sufficiently great to ensure, that the filmtears before the reinforcement is displaced.

Preferred adhesives are permanent tack adhesives particularly thosebased on resin modified rubbers.

Where polyester, for example poly(ethylene terephthalate), is employedeither as the film to be reinforced or as the reinforcing material,bonding of the film and reinforcement may conveniently be effected byemploying the polyester in the form of a laminate with an easily heatsealable material, for example polyethylene or vinylidene chloride, thebonding being brought about using the heat sealable plastic as a cementusing conventional heat bonding techniques. It will be apparent to theskilled man that other known methods of improving the ease with whichadhesion can be effected may be employed, e.g. electrical discharge andchemical surface treatment of polyethylene. Film or reinforcement whichis a laminate of materials having different properties, e.g. to impartease of adhesion or bonding by other methods may be employed.

The strength of the reinforcement is not critical, since the use of evenquite modest reinforcement is generally advantageous. The strength ofthe reinforcement will usually be a function of its composition and itwidth and thickness. These may be varied at will, but the thickness ofthe reinforcement will not be so great that its flexibility is lost.Usually the reinforcement will be between 0.01 and 2 mm thick,preferably between 0.05 and 0.5 mm thick. It will be apparent that thethicker reinforcement will be employed on heavy duty articles made fromthick plastic film, e.g. agricultural sacks.

Thus, since the film to which the reinforcement may be applied willusually be from 0.01 to 0.2 mm thick, preferably from 0.02 to 0.1 mm,and more preferably from 0.03 to 0.075 mm thick, the thinnerreinforcement will usually be applied to the thinner films, and thethickest reinforcement to the thicker films. It is often found that asuitable combination will be the use of film and reinforcement ofsimilar thickness.

The reinforcement may be of any colour, and may be patterned or carryscript, e.g. indicating where the tear should be made.

The surface of the reinforcement may be roughened, e.g. by abrasion, bya surface moulding operation or merely as a result of exposure of atextile surface. Gripping points by means of which the reinforcement maybe gripped conveniently to facilitate tearing may form an integral partof the reinforcement, or may be attached thereto. 7

The invention may be applied to film to be torn from a point which isnot at an edge, for example where the film is in the form of acylindrical tube which is to be tom around its circumference at adistance from the ends of the tube; and where the tear is to originateat a point which is not at an edge it has been found desirable toperforate the film at a point on the line of weakness of thereinforcement at or near the point (hereinafter referred to as the givepoint) at which tension is first applied to the film at the commencementof the tearing operation. While the perforation may be made at the givepoint itself we have found that it is advantageous to make theperforation sufficiently close to the give point to weaken the filmremaining between the give point and the perforation so that tearing maycommence with less effort than if the perforation were not present.

While the perforation may be effected by any appropriate cutting orpenetrating means, for example scissors or knife blade, we have foundthat mere pricking of the plastic film, as with a pin point, may bequite sufficient to effect the desired increase in tearability.

The improvement in tearability obtained by such a perforating operationhas been found to be advantageous not only when the give point is not atan actual edge that is sharply defined but also when films which aretear resistant either due to thickness or to the inherent strength ofparticular materials, e.g. Melinex (RTM), are to be torn.

Preferably a means for effecting perforation of the plastic filmaccording to this aspect of the invention is included as a component ofthe plastic film product incorporating flexible reinforcement asdescribed above, and we have found this particularly convenient if thereinforcement means employed project beyond the surface of the plasticfilm to provide gripping means by which the reinforcement may be grippedduring the tearing operation; the perforating means may then form acomponent of the gripping means. The perforating means may betemporarily or permanently affixed to the gripping means. When thegripping means comprises two or more strips or tapes two surfaces ofwhich lie together, preferably by weak adhesion, the perforating meansmay be located between the said surfaces so that it is protected untilrequired for use, when it may be exposed.

The invention is now described in more detail with reference to someembodiments thereof and with the aid of the accompanying drawings (notto scale) in which:

FIGS. 1 to 3 are perspective views of plastic, e.g. polyethylene, filmmodified according to the invention;

FIGS. 4 and 5 show cross-sections of the films of FIGS. 2 and 3 throughthe line A A;

FIGS. 6 and 7 show alternative cross-sections for each of the filmsshown in FIGS. 2 and 3;

FIG. 8 is a perspective view of a bag or sack modified in one way inaccordance with the invention,

FIGS. 9 to 13 show an embodiment of the invention in which thereinforcement can be employed as a temporary closure means;

FIGS. 14 through 16 show the principle of the invention applied to abag;

FIGS. 17(a), 17(b), 17(0) and 17(d) are diagram matic illustrations of asheet of plastic film to which is applied a pair of reinforcementstrips, additionally illus trating the effect of a perforation or otherlocalized line of weakness;

FIGS. 18(a) and 18(b) illustrate a method of imbedding a perforatedmeans in the reinforcement strip;

FIGS. 19(a), 19(b), 19(0) and 19(d) illustrate a perforating means madeby punching a hole through a piece of metal so that the raised portionconstitutes a serrated edge; and

FIGS. 20(a), 20(b) and 20(c illustrate the application of the inventionto a tubular plastic film article which hasno sharply defined edge atwhich the tear is to commence.

Referring to FIG. 1, a thin film of polyethylene (1) has applied to thesurface thereof a plurality of reinforcement strips (2) each consistingof a double line of an acrylic-based paint applied by a printingoperation following extrusion and cooling of the film. The reinforcementstrips may be applied at predetermined distances apart, or to a morecomplex predetermined pattern, to facilitate tearing of the film to adesired outline.

FIG. 2 represents a film to the surface of which has been bondedreinforcement 2 consisting of a strip of linen scrim having a line ofweakness along its length and which extends beyond one edge of the filmand has at its end an incised notch 3 which aids tearing. In FIG. 3, thestrip of linen scrim is replaced by two abutting or closely spacedparallel strips, 4,5 of self-adhesive plastic tape, e.g. Sellotape(Registered Trade Mark). With this version of the invention there is, ofcourse, no need for an incision.

The articles of FIGS. 2 and 3 are shown in crosssection along the lineA-A in FIGS. 4 and 5 respectively, in which the thickness of the plasticfilm and of the reinforcement are very much exaggerated.

In an alternative embodiment, the reinforcement may be part or whollywithin the thickness of the film, as illustrated in FIGS. 6 and 7.

FIG. 8 represents a bag or sack in accordance with the invention. Itcomprises a tube of, for example, polyethylene film flattened to providetwo walls 11, 12 sealed together along the line XY e.g. by heat sealing,and to be sealed along or near the line X'Yf after being filled, e.g.with fertiliser. Bonded to or placed within each wall and'arrangeddiagonally across a corner of the bag is a strip 13 of linen scrim. Thestrips are arranged so that they are naturally in superimposed relationship or else may be brought into such relationship for tearing, andone end of each strip extends beyond one edge of the bag, the two freeends preferably being bonded together and thebonded ends being providedwith an incised notch 14 to aid tearing. The reinforcement may beapplied to, or incorporated in, the plastic tube during its manufacture.

FIGS. 9 to 13 show a container20 made from plastic film in which thereinforcement consists of two linen strips 21 and 22 one of thestripsbeing longer than the other and extending beyond it at both ends asshown, so that an adhesive portion of strip 23 is exposed at each sideof the container. FIG. shows the container closed, with the exposedadhesive portions of 21 pressed against the sides of the container. FIG.11 shows the container beingtom open, the sealed end portion 24 beingremoved and leaving the opened package as shown in FIG. 12. Temporaryreclosure of the container may be effected, as illustrated in FIG.'13,by folding the free end of the container and pressing the adhesiveportions of the remaining reinforcement 21 against the container sidesas before. The adhesive employed in an application such as this isnecessarily one which allows the bond to be broken and'remade, (e.g. apermanent tack adhesive).

FIGS. 14-:16 show the same principle applied to a bag, the top of whichcan be rolled down for closure as the contents are progressively used.

The remaining Figures, i.e. FIGS. 17a-l7d, 18a-18b,

ISM-19d and a-20d, illustrate the use of perforating means in accordancewith the invention.

InFIG. 17, FIG. 17a is a diagrammatic representation of a sheet ofplastic film 1 to which is applied a pair of reinforcing strips, thestrips being applied to the same side of the film substantially parallelto each other with a narrow longitudinal gap between them, and progivepoint in which the perforation may typically be made. This area willusually be within about 0.5 cm. of the give point. FIG. 17b is adiagrammatic view of the same system showing the effect of a perforation26 adjacent to the give point when the tearing operation is commenced bypulling apart the ends of the strips in the direction of the arrows.

Although in the above diagrams two parallel reinforcing strips are shown(since the illustration of the principleof the invention is there-byfacilitated) it is not, of course, essential to use two parallel strips;when a single reinforcing strip comprising a localised line of weaknessis applied to one side of the film perforation of thefilm in theappropriate area may be effected by application .of the perforatingmeans to the exposed surface of the film. This is illustrated insectional view in FIG. 17c in which 1 is the plastic film, 27 is thereinforcing strip'and 28 is a perforating means (e.g. a pin). Whensingle reinforcing strips each comprising a localised line of weaknessare applied to both sides of the film, the perforation in the plasticfilm may be effected by penetrating the reinforcement itself at a pointon the line of weakness. This is shown in FIG. 17d, which is a sectionalview of a plastic bag or like article having two walls formed out of acontinuous. piece of plastic film having a creased edge29. Tworeinforcing strips, 30 and 31, are applied, one to each wall ofthe bag,and adhere to each other region in which. they project beyond theedge ofthe bag. A perforating means 28 is shown penetrating one reinforcingstrip 31 and the film constituting the walls of the bag adjacent to thegive point at the edge of the bag. a FIG. 18 illustrates one method ofembedding a perforating means, e.g. a small pointedpiece .of metal 28 inthe reinforcement, in an embodiment in which two pairs of parallelreinforcing strips are attached, one pair to edge side, of the film 1.FIG. 18a is a sideview and F IG; 18b is an end-on view of the strips ofreinforcing material 32, 32, 33, 33'. The perforating means is securedbetween the adhesive strips in the region in which the strips projectbeyond the edge of the film,

and its point may be exposed by separating the ends of jecting some waybeyond the edge of the film. The

shaded area 25 represents the region adjacent to the the strips in thedirection of the arrows.

FIG. 19 illustrates a perforating means 34, shown in perspective in FIG.19a, made by punching a hole through a pieceof metal so that the edgesof the hole are raised and constitute a sharp serrated edge. FIG. 19b isa sectional view showing the perforatingmeans 34 enclosed between twoadhesive reinforcing strips 35, 36 projecting beyond'the edge of thefilm], so that it is protected until required for use.

FIG. 19c shows an'altemative method'of affixing a perforating means asdescribed above by welding it to a plastic reinforcing strip. FIG. is aperspective view of such a strip, 37, incorporating a perforating means38, and FIG. 19d is a section along the line AA of FIG. 19c.

FIG. 20 illustrates the application of the invention to a tubularplastic film article. which has no sharply defined edge at which thetear is to commence. The teambility of such an-article may be improvedmerely by ap-,

plying to its surface reinforcing material. This is illustrated in FIG.20a, which is a perspective side view of a tubular film article 39having applied to it two parallel reinforcing strips 40, 41, each ofwhich contacts the entire circumference of the tubular article and hastwo ends which are superimposed on each other in the region of thestrips'projecting beyond the wall of the 7. tube. However, it isparticularly advantageous to perforate the plastic film before it istorn when it is in the form of a tube, and this may be done by means ofa device as illustrated in FIG. 19a, attached to the reinforcement asillustrated in FIG. 19b or FIG. 19d, and used as illustrated in FIG. 20bwith a perspective side view showing one end of one reinforcing strip40, bearing the perforating means 34, detached from the other end of thesame strip and brought into contact with the wall of the tubular articleon the line of weakness between the reinforcing strips so as to effectperforation of the film. The tubular film article may then be torn asshown in FIG. 20c.

The following Examples serve to further illustrate the invention.

EXAMPLE 1 A single layer of low-density polythene film, 0.005 inchesthick and approximately six inches square had applied across it, fromone edge to the other, a strip of 0.5 inch side linen fabric adhesivetape (Sellotape Products Ltd.). The film was turned over and a secondstrip of the same tape applied to the other side of the film,superimposed upon the first. The tapes projected approximatley one inchfrom the edge of the film, and were stuck together in this region. A cutwas made in the double layer of tape, extending from the end of thetapes along the centre of the tapes for approximately 0.5 inch; thatis,not extending as far as the edge of the film. When the ends of the tapeswere grasped with both hands, ne finger and thumb gripping one each sideof the cut, a tearing action caused a smooth tearv to propagate alongthe centre of the tapes and completely across the film.

EXAMPLE 2 the pairs of tapes.

EXAMPLE 3 Two sheets of film as in Example 1 were superimposed andheat-sealed along all four edges so as to make a closed bag. Two stripsof adhesive fabric tape as in Example 1 wereapplied diagonally acrossone corner of the bag, extending beyond the edge for approximately oneinch, one strip being applied to each face of the bag, and the twostrips being superimposed on each other. A cut was made in the end ofthe tapes as in Example I, and tearing along the centre of the tapescaused the corner of the bag to be torn off cleanly.

EXAMPLE 4 A bag as in Example 3 had two strips of fabric tape as inExample l applied in superimposed relationship from the centre of thebag to the centre of one of the edges of the bag and projecting beyondthe edge for approximately one inch. A cut was made in the tapes, and

EXAMPLE 6 Film and tapes were used as in Example 1, but before the tapeswere tom, the tip of a scalpel blade was used to penetrate one layer oftape and the layer of film, approximately 0.1 inch from the edge of thefilm. Tearing of the film along the centre line of the tapes wasinitiated much more easily than in Example 1.

EXAMPLE 7 A sheet of Melinex (RTM) poly(ethylene terephthalate) filmbiaxially drawn, 0.001 inch thick and approximately six inches squarehad applied across it, from one edge to the other, two parallel stripsof black pvc adhesive tape (Klingfast RTM 2702, Rotunda Ltd, Manchester,England) each 0.5 inch wide and approximately 0.007 inches thick with anarrow gap of approximately 0.05 inches between them. A second pair oftapes was applied to the opposite side of the film, in' superimposedrelationship. The two pairs of tapes projected beyond one edge of thefilm, and adhered together in overlapping region. Tearing of the filmbetween the strips of tape required considerable force to initiate, butthen progressed smoothly and cleanly between the strips ofreinforcement.

EXAMPLE 8 A tube of Melinex (RTM) film, 0.001 inch thick, andapproximately 4 inches diameter had applied to it two strips of the pvcadhesive tape of Example 7, each strip running round the circumferenceof the tube, and the two ends of each strip projecting approximately oneinch from the wall of the tube and adhering together. The two stripswere applied parallel and with a narrow gap (approximately 0.05 inches)between them. The tube could not easily be torn open by pulling thetapes apart. A small perforation was then made in the wallof the tubebetween the tapes, using a pointed piece of metal adhering to one of thetapes. The tube could then be torn open smoothly along the lineseparating the tapes.

EXAMPLE 9 EXAMPLE 10 A strip of linen tape about 2 cm wide, 0.5 mmthick, 20 cm long and of mesh size 1 mm. was bonded to a sheet ofpolyethylene film 0.5 mm thick by heat welding. This involved applyingthe tape to one surface of the film and laying on the surface of thetape a heating iron heated to about C (i.e. sufficient to soften thepolyethylene sheet) so that the tape could be pressed into it to a depthof about 0.2 mm. The tape firmly bonded to the sheet after cooling. Anotch was made in the end of the tape which extended slightly (1 cm)beyond one edge of the film. On tearing the tape from this notch alongits length the tape toreclearly, as did the film to which it was bonded.

What we claim is:

1. A container comprising a tube of plastic film sealed at one end toprovide a bag having two walls and a common sealed edge, a firstflexible reinforcement strip attached to one walland extending from apoint in said common edge diagonally across a corner of said bagoutwardly to a point beyond said bag, another similar flexiblereinforcement strip attached to the other wall and extending from saidpoint in said common edge diagonally across the same corner of said bagand outwardly beyond the bag so as to be in superimposed relationshipwith said first strip, the ends of said strips which extend beyond saidbag being bonded together and said bonded ends being provided with anotch defining a line of localized weakness whereby tearing of saidstrips along said notch pennits tearing of said container to open thesame.

2. A container according to claim 1 wherein the reinforcement stripcomprises a woven textile web or plastic sheet. I

3.A container according to claim 2 wherein the reinforcement stripcomprises regenerated cellulose, polyamide, polyester, polyurethane,polyvinyl, acrylic or polyolefin polymer.

4. A container according to claim 2 wherein the rein- I forcement stripconsists of two substantially parallel strips of reinforcing materialdisposed in abutting or closely spaced edge-to-edge relationship. 5. Acontainer according to claim 2 wherein the reinforcement strip is from0.01 2 mm. thick.

1. A container comprising a tube of plastic film sealed at one end toprovide a bag having two walls and a common sealed edge, a firstflexible reinforcement strip attached to one wall and extending from apoint in said common edge diagonally across a corner of said bagoutwardly to a point beyond said bag, another similar flexiblereinforcement strip attached to the other wall and extending from saidpoint in said common edge diagonally across the same corner of said bagand outwardly beyond the bag so as to be in superimposed relationshipwith said first strip, the ends of said strips which extend beyond saidbag being bonded together and said bonded ends being provided with anotch defining a line of localized weakness whereby tearing of saidstrips along said notch permits tearing of said container to open thesame.
 2. A container according to claim 1 wherein the reinforcementstrip comprises a woven textile web or plastic sheet.
 3. A containeraccording to claim 2 wherein the reinforcement strip comprisesregenerated cellulose, polyamide, polyester, polyurethane, polyvinyl,acrylic or polyolefin polymer.
 4. A container according to claim 2wherein the reinforcement strip consists of two substantially parallelstrips of reinforcing material disposed in abutting or closely spacededge-to-edge relationship.
 5. A container according to claim 2 whereinthe reinforcement strip is from 0.01 - 2 mm. thick.